Life-History and Spatial Determinants of Somatic Growth Dynamics in Komodo Dragon Populations

Abstract

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world’s largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

Isolating Chromosomes of the Komodo Dragon: New Tools for Comparative Mapping and Sequence Assembly

“…Considered "vulnerable" by the International Union for Conservation of Nature [IUCN, 2012], V. komodoensis is a keystone and umbrella species for the Monsoon forest ecosystem [Mills et al, 1993;Roberge and Angelstam, 2004] and plays an important role in the Lesser Sunda ecotourism development. A number of studies have been conducted on the population ecology, genetics, physiology, microbiology, management, and conservation of both captive and wild populations [e.g., Auffenberg, 1981;Ciofi et al, 1999;Montgomery et al, 2002;Murphy et al, 2002;Ciofi and de Boer, 2004;Watts et al, 2006;Ciofi et al, 2007;Jessop et al, 2007;Fry et al, 2009;Laver et al, 2012;Purwandana et al, 2014Purwandana et al, , 2015Ariefiandy et al, 2015;Bishop et al, 2017]. However, information on cytogenetics and genomics of this species is limited.…”

Komodo Dragon Predation on Crab-Eating Macaques at the Rinca Island’s Visitor Centre, Indonesia

“…The Komodo National Park prioritizes the management of the Komodo dragon population and focuses its efforts on only 3 prey species, i.e., rusa deer, feral pigs and water buffalo [Auffenberg, 1981;Jessop et al, 2006;Ariefiandy et al, 2013;Laver et al, 2017]. The management rarely considers the population dynamics of M. fascicularis as an alternative but substantial prey for the dragons.…”

Molecular Sex Determination of Captive Komodo Dragons (Varanus komodoensis) at Gembira Loka Zoo, Surabaya Zoo, and Ragunan Zoo, Indonesia

“…Body length measurements were obtained from 81 Komodo dragons at Indonesian Zoos (Gembira loka, Surabaya, and Ragunan). According to Laver et al (2012), Komodo dragons grow until they reach breeding age (about 7 years) after which the growth trajectories diverge, with females tending towards a smaller maximum size than males. Male Komodo dragons continue to grow until reach 160 cm in SVL size (a total length of 3 meters).…”

“…html). Laver et al (2012) used SVL-defined as the straight line distance measured between the tip of the snout and the cloaca to the nearest millimeter-as the measure of growth for each individual. In our study, measurements were made using a flexible fiberglass tailor's tape.…”